The impact of short-term acute heat stress on the rumen microbiome of Hanwoo steers

Abstract

Heat stress negatively affects cattle productivity by reducing feed intake. In the present study, we assessed if the rumen microbiome composition of Hanwoo steers was altered by exposure to heat stress. Rumen samples were collected from four Hanwoo steers that were individually housed in climate-controlled chambers with 60% humidity and environmental temperatures of: 1) 15℃ (0-day group), 2) 35℃ for 3 days (3-day group), and 3) 35℃ for 6 days (6-day group). The total community DNA of samples was extracted, and 997,843 bacterial and 1,508,770 archaeal sequences were analyzed using next-generation sequencing. Assessment of the relative abundances revealed 15 major phyla of which Bacteroidetes was found to be the most dominant. After 3 days of heat stress exposure there were no significant changes in the rumen microbiome composition, except for a decrease in the Planctomycetes. However, after 6 days of heat stress exposure, we found that the relative abundance of fibrolytic Ruminococcaceae had decreased while that of lactate-producing Lactobacillaceae and amylolytic Prevotella and Ruminobacter had increased. The normal rumen microbiome of Hanwoo cattle was shown to be disrupted after 6 days of heat stress, which led to the decrease in fibrolytic bacteria that are sensitive to low pH and the increase in both lactate-producing and amylolytic bacteria. We have demonstrated that the microbiome composition of the rumen is affected by acute heat stress. Our findings may contribute to the development of different feeding strategies to restore heat stress-induced disruption of the rumen microbiome.

Fecal Microbiota and Their Association With Heat Stress in Bos Taurus

“…This phylum was already reported as significant in heat stress analysis of pigs reported by He [37]. Chloroflexi and Planctomycetes significantly associated with rectal temperature were also reported as a significant phyla in the analysis of short-term acute heat stress on the rumen microbiome of Hanwoo steers [33].…”

Seasonal Influence on Rumen Microbiota, Rumen Fermentation, and Enteric Methane Emissions of Holstein and Jersey Steers under the Same Total Mixed Ration

“…The higher abundance of R. bromii in winter suggests higher amylolytic activity through their preferential growth in the rumen, which might be attributed to higher VFA production in winter. Baek et al [ 83 ] revealed that heat stress reduced the abundance of fibrolytic Ruminococcaceae while increasing the lactate-producing Lactobacillaceae and amylolytic Prevotella and Ruminobacter in Hanwoo steers. Likewise, Zhao et al [ 84 ] reported that heat-stressed dairy cows had a significantly higher relative abundance of Streptococcus , unclassified Enterobacteriaceae , Ruminobacter , Treponema , and unclassified Bacteroidaceae.…”

Heat stress on microbiota composition, barrier integrity, and nutrient transport in gut, production performance, and its amelioration in farm animals

“…The modern poultry genotypes are more susceptible to HS due to marked growth rate along with greater metabolic activity [ 1 ]. An earlier study with the use of a culture technique showed that the number of Enterobacteriaceae was decreased, whereas Streptococcus and Staphylococcus numbers were increased by HS in the small intestine of chickens [ 29 ]. Microbial community composition in the ileum and cecum of chickens was also altered by heat exposure to 30°C for 24 h [ 12 ].…”